2. April 1, 2003Lynn Cominsky - Cosmology A3501 Professor Lynn Cominsky Department of Physics and Astronomy Offices: Darwin 329A and NASA EPO (707) 664-2655 Best way to reach me: lynnc@charmian.sonoma.edu Astronomy 350 Cosmology

3. April 1, 2003Lynn Cominsky - Cosmology A3502 Group 10  Timothy Blakley  Kira Kayler  Lance Lilly  David Minehan

4. April 1, 2003Lynn Cominsky - Cosmology A3503 Big Bang Timeline We are here Today’s lecture

5. April 1, 2003Lynn Cominsky - Cosmology A3504 Cosmic Microwave Background  Discovered in 1965 by Arno Penzias and Robert Wilson who were working at Bell Labs  Clinched the hot big bang theory Excess noise in horned antennae was not due to pigeon dung!

6. April 1, 2003Lynn Cominsky - Cosmology A3505 CMBR and cosmology  Take a trip in time/out in space to put "earliest light" in perspective movie

7. April 1, 2003Lynn Cominsky - Cosmology A3506 Where is the CMBR?  Map of redshift vs. time after Big Bang CMBR Z=1000 Universe has expanded and cooled down by 1+z (about 1000) since the photons last scattered off the CMBR

8. April 1, 2003Lynn Cominsky - Cosmology A3507 CMBR  Photons in CMBR come from surface of last scattering – where they stop interacting with matter and travel freely through space  CMBR photons emanate from a cosmic photosphere – like the surface of the Sun – except that we are inside it looking out  The cosmic photosphere has a temperature which characterizes the radiation that is emitted  It has cooled since it was formed by more than 1000 to 2.73 degrees K

9. April 1, 2003Lynn Cominsky - Cosmology A3508 Cosmic Background Explorer  3 instruments: FIRAS, DMR and DIRBE  Cryogens ran out on 9/ 21/ 90 ending observations by FIRAS and longer wavelengths of DIRBE  DMR and the shorter wavelengths of DIRBE operated until 11/23/93

10. April 1, 2003Lynn Cominsky - Cosmology A3509 COBE data/DIRBE  Diffuse InfraRed Background Experiment  IR background is produced by dust warmed by all the stars that have existed since the beginning of time  Limit to energy produced by all stars in the Universe

11. April 1, 2003Lynn Cominsky - Cosmology A35010 COBE data/FIRAS  Far InfraRed Absolute Spectrophotometer

12. April 1, 2003Lynn Cominsky - Cosmology A35011 COBE data/FIRAS  FIRAS results show that 99.994% of the radiant energy of the Universe was released within the first year after the Big Bang  Data match the Big Bang predictions so exactly that the error bars are within the curve itself Residuals from a 2.728 (+/- 0.004) degree Kelvin blackbody

13. April 1, 2003Lynn Cominsky - Cosmology A35012 COBE data/FIRAS  The CMBR is described by the most perfect blackbody spectrum ever measured  Blackbody spectra are produced when material is thick and dense, so that photons must scatter many times before they escape  The photons must therefore have been emitted from dark, thick matter at a much earlier time  The CMBR energy was emitted when the Universe was 10 6 times smaller and hotter than it is now. Photons continued to scatter until the Universe was 10 -3 its present size

14. April 1, 2003Lynn Cominsky - Cosmology A35013 COBE DMR  Differential Microwave Radiometer  3 different wavelengths  2 antennae for each wavelength, 7 degree beam  Pointed 60 degrees apart DMR work featured in George Smoot’s “Wrinkles in Time”

15. April 1, 2003Lynn Cominsky - Cosmology A35014 COBE data/DMR  Dipole due to movement of Solar System warm cool

16. April 1, 2003Lynn Cominsky - Cosmology A35015 COBE data/DMR  Dipole removed to show “wrinkles”

17. April 1, 2003Lynn Cominsky - Cosmology A35016 COBE data/DMR  Fluctuations in CMB seen by DMR are at the level of one part in 100,000 Blue spots mean greater density Red spots mean lesser density (in the early Universe)

18. April 1, 2003Lynn Cominsky - Cosmology A35017 CMBR Fluctuations  COBE measures the angular fluctuations on large scales, down to about L=16

19. April 1, 2003Lynn Cominsky - Cosmology A35018 CMBR Fluctuations  Determining the spectrum of fluctuations in the CMBR can directly differentiate between models of the Universe Angular size of fluctuation How much power there is

20. April 1, 2003Lynn Cominsky - Cosmology A35019 CMBR Fluctuations  Current data favor a peak near L Eff = 210  This is consistent with the sCDM (standard Cold Dark Matter) and  CDM models (CDM + cosmological constant)  Both describe a flat (  =1) Universe

21. April 1, 2003Lynn Cominsky - Cosmology A35020 CMBR Fluctuations  For a given model (e.g., sCDM) the fluctuation spectrum can also be used to directly determine the Hubble constant

22. April 1, 2003Lynn Cominsky - Cosmology A35021 BOOMERanG Photos from previous flight in Antarctica

23. April 1, 2003Lynn Cominsky - Cosmology A35022 BOOMERanG  Balloon Observations Of Millimeter Extragalactic Radiation and Geophysics  12 - 20 arc min resolution  Flight on 12/29/99 – 1/8/00 saw flat Universe since fluctuations were about 1 degree  0.85<  tot  <1.25  Supports cosmological constant   =0.6 (accelerating Universe), since  M is only about 0.2-0.4 (including dark matter)

24. April 1, 2003Lynn Cominsky - Cosmology A35023  (total)  M +   where  M = matter density (including regular and dark matter)   = cosmological constant or dark energy density  tot = density/critical density Density of the Universe Perlmutter et al. 40 supernovae SN data

25. April 1, 2003Lynn Cominsky - Cosmology A35024 Wilkinson Microwave Anisotropy Probe (WMAP)  Selected by NASA in 1996  Launched June 30, 2001 to L2  Has measured fluctuations in CMBR on a scale of 0.2 - 1 degrees (vs. 7 o for COBE) and filled in the fluctuation plot Key results: Hubble constant is 71 km/sec/Mpc (to within 5%) Age of the Universe is 13.7 billion years old (to within 1%!) First stars appeared at t = 200 million years after the BB Universe is geometrically flat

26. April 1, 2003Lynn Cominsky - Cosmology A35025 WMAP Orbit  L2 is one of the 3 semistable points in the Earth-Sun binary system  Another body can orbit at this point at a fixed distance from the Earth and the Sun with corrections every 23 days

27. April 1, 2003Lynn Cominsky - Cosmology A35026 WMAP

28. April 1, 2003Lynn Cominsky - Cosmology A35027 Making the MAP  All five WMAP frequency band maps combine to create the full-sky CMB map. movie

29. April 1, 2003Lynn Cominsky - Cosmology A35028 MAP corrections  Removing the dipole caused by Earth’s motion

30. April 1, 2003Lynn Cominsky - Cosmology A35029 MAP corrections  Removing the foreground signal from our Galaxy to show the background

31. April 1, 2003Lynn Cominsky - Cosmology A35030 Universe’s Baby Pictures Red is warmer Blue is cooler Credit: NASA/WMAP

32. April 1, 2003Lynn Cominsky - Cosmology A35031 Compare to COBE  The WMAP image brings the COBE picture into sharp focus. movie

33. April 1, 2003Lynn Cominsky - Cosmology A35032 Compare MAPs at other wavelengths  Visible to microwave galaxy images  Compare the dynamic range movie

34. April 1, 2003Lynn Cominsky - Cosmology A35033 Geometry See how parallel laser light beams fired by the space slug are affected by the geometry of space

35. April 1, 2003Lynn Cominsky - Cosmology A35034 WMAP measures geometry

36. April 1, 2003Lynn Cominsky - Cosmology A35035 WMAP cosmology  Content of the Universe: 4% Atoms 23% Cold Dark Matter 73% Dark energy  Fast moving neutrinos do not play any major role in the evolution of structure in the universe. They would have prevented the early clumping of gas in the universe, delaying the emergence of the first stars, in conflict with the new WMAP data.

37. April 1, 2003Lynn Cominsky - Cosmology A35036 WMAP supports inflation  Inflation - a VERY rapid expansion in the first 10 -35 s of the Universe – predicts: That the density of the universe is close to the critical density, and thus the geometry of the universe is flat.geometry That the fluctuations in the primordial density in the early universe had the same amplitude on all physical scales.fluctuations That there should be, on average, equal numbers of hot and cold spots in the fluctuations of the cosmic microwave background temperature.  WMAP sees a geometrically flat Universe

38. April 1, 2003Lynn Cominsky - Cosmology A35037 WMAP angular power spectrum

39. April 1, 2003Lynn Cominsky - Cosmology A35038 Planck  ESA mission to be launched in 2007  Will measure entire sky to 10’ to 2 parts per million  Will give better information than WMAP for L eff from 600 to 2000

40. April 1, 2003Lynn Cominsky - Cosmology A35039 Planck COBE vs. Planck What Planck will see

41. April 1, 2003Lynn Cominsky - Cosmology A35040 X-ray Background  Discovered over 35 years ago in rocket flights  Early theories explained the X-ray background as a diffuse, hot gas which filled the Universe  Data from Einstein Observatory showed about 50% of the background could be due to quasars  ROSAT data explained about 60% of the 1-2 keV X-ray background with quasars  However flux and energy spectra did not add up correctly if the background was all quasars

42. April 1, 2003Lynn Cominsky - Cosmology A35041 X-ray Background  ROSAT 0.75 keV map Shows smooth blue background plus bright superbubble ring at D=150 pc with R= ~100 pc

43. April 1, 2003Lynn Cominsky - Cosmology A35042 Chandra data  At least 80% of X-ray background is made of discrete sources including two new types:  Very distant galaxies with faint black holes  Bright black holes without visible galaxies Results were from comparing Chandra data to deep optical surveys from Keck

44. April 1, 2003Lynn Cominsky - Cosmology A35043 CGRO/EGRET data  30-40% of gamma-ray background is unresolved and extragalactic in origin

45. April 1, 2003Lynn Cominsky - Cosmology A35044 Gamma-ray Background  Simulated sky as seen by GLAST after 1 year of observation  Key goal to determine if extra-galactic gamma-radiation is from discrete sources

46. April 1, 2003Lynn Cominsky - Cosmology A35045 Web Resources  Cosmic Background Explorer http://space.gsfc.nasa.gov/astro/cobe/cobe_ho me.html  Wilkinson Microwave Anisotropy Probe http://map.gsfc.nasa.gov  Planck mission http://astro.estec.esa.nl/SA- general/Projects/Planck/ http://astro.estec.esa.nl/SA- general/Projects/Planck/  BOOMERanG http://www.physics.ucsb.edu/~boomerang/

47. April 1, 2003Lynn Cominsky - Cosmology A35046 Web Resources  Ned Wright’s CMBR pages http://www.astro.ucla.edu/~wright/CMB-DT.html  Bell Labs Cosmology Archives http://www.bell- labs.com/project/feature/archives/cosmology/http://www.bell- labs.com/project/feature/archives/cosmology/  GLAST project outreach web site http://www-glast.sonoma.edu http://w  George Smoot’s group pages http://aether.lbl.gov/http://aether.lbl.gov/  Chandra X-ray Background Results http://chandra.harvard.edu/press/00_releases/press_0114 00bg.html